Microtome



Jan. 24, 1967 J. R. M CULLOCH 3,299,753

MICROTOME Filed Nov. 12, 1964 2 Sheets-Sheet 1 Qcmoq AQT 7 INVENTOR Jot-\M Q. MQCULLOCH ATTORNEY 1957 J. R. MCCULLOCH MICROTOME 2 SheetsSheec Filed Nov. l2, 1964 Fla. 4

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ATTOZNEY United States Patent 3,299,758 MICROTOME John R. McCulloch, 427 Via Del Plano, Novato, Calif. 94947 Filed Nov. 12, 1964, Ser. No. 410,836 7 Claims. (Cl. 83-410) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to an improved laboratory instrument, and more particularly to an improved microtome capable of cutting ultra-thin specimen sections to be viewed by a microscope. The invention is related to and constitutes an improvement over United States Patents No. 2,822,726, issued February 11, 1958, and No. 2,948,- 190, issued August 9, 1960. Both patents were issued to I. Blum. The improvement is concerned with the knifeholding stage of the Blum microtome and with the specimen guide plate used in that microtome. By means of these improvements, it is possible to use the Blum microtome to obtain specimen sections taken in perpendicular planes and consequently to obtain a three dimensional view of the subject under study when the sections are viewed side by side.

An object of the invention is to provide an improved micro-tome knife-holding stage having two knives whose cutting surfaces are substantially perpendicular to each other, whereby the specimen to be examined can be alternately cut in perpendicular planes as it is passed over each cutting surface. The sections thus obtained provide a three dimensional view of the cells or organelles under study and consequently permit their more accurate reconstruction.

Another object of the invention is to provide an improved knife-holding stage wherein the two knives are mounted so as to be adjustable both laterally and longitudinally relative to the stage.

Another object of the invention is to provide a guide plate for a microtome which can be adjusted so as to cause the specimen to be pressed against either of two knife cutting surfaces or to by-pass both cutting surfaces, as desired.

The structural features of the invention are illustrated in the accompanying drawings in which:

FIG. 1 is a side perspective view of the microtome to which this invention applies, but with the knife-holding stage omitted;

FIG. 2 is a sectional view taken on line 22 of FIG. 1 showing the interrlation of the microtome frame and the knife-holding stage of this invention;

FIG. 3 is a top view of the knife-holding stage;

FIG. 4 is a view of the knife-holding stage, partly in section, taken along line 44 of FIG. 3;

FIG. 5 is a side view of the knife-holding stage;

FIG. 6 is an elevation view of the guide plate of this invention, as it is attached to the microtome frame, showing the plate in position to cause the specimen to bypass both knives;

FIG. 7 is an elevation view showing the guide plate in position to cause the specimen to be pressed against the first knife blade;

FIG. 8 is an elevation view showing the guide plate in position to cause the specimen to be pressed against the second knife blade;

FIG. 9 is a persepotive view of the detached guide plate; and

FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. 6.

Referring to the drawings, FIG. 1 shows the microtome to which this invention pertains. The microtome is de- "ice scribed in detail in Patent No. 2,822,726. Its essential features includes the base 1 having a groove 2 along its longitudinal axis, a specimen-advancing bar 3, an upper frame 4 to which bar 3 is pivotally attached, a vertical frame 5 to which guide plate 6 is attached, and the knife- .holding stage, not shown in FIG. 1. The specimen 7 is attached to advance bar 3. By means of hand crank 8 or other drive means the specimen bar 3 is caused to move in a varying cyclic pattern so as to press the specimen 7 alternately against each knife blade. The specimen advance means and drive means are shown in detail in the Blum patents and, since they do not concern this invention, need not be further described here.

FIG. 2 shows the interrelation of the microtome base 1 and the base 9 of the knife-holding stage. The stage base 9 is locked to the microtome base 1 by tightening lock screw 10. This action draws locking plate 11 against the top of groove 12 cut in the side wall of base 1. Spring 13 aids in releasing plate 11 from locking position. Right knife mount 14 and left knife mount 15 are slidably mounted, tongue in groove, in stage base 9.

FIGS. 3, 4, and 5 show details of the knife-holding stage of this invention. Right and left knife mounts 14 and 15 are individually slidable in stage base 9. Fine adjustment is obtained by means of adjusting screws 16 which extend through lugs 17 of base 9 into mounts 14 and 15. Adjusting screws 16 provide fine individual longitudinal adjustment of the knife blades while locking plate 11 provides course longitudinal adjustment of both blades simultaneously. Lateral adjustment for the knives is provided by adjusting screws 18, threaded into the inside of the knife-holding barrels. Adjusting screws 18 are turned in or out by turning knobs 19, the shafts 20 of which pass through collars 21 attached to knife mounts 14 and 15. Lock screws 22 prevent movement of the knife holder barrels after the knives are in the desired position.

Knives 23 and 24 are removably mounted in knife holders 25. The knives are held in place and at the desired cutting angle by pressure plates 26 inset in holders 25. Lock screws 27 are threaded through holders 25 and are connected to plates 26. Knives 23 and 24 are set in diagonal slots in holders 25 at 45 degree angles relative to the lateral axis of knife holders 25. The knives converge in the direction of the cutting surfaces. Because of the angle of the diagonal slots, the cutting surfaces of the knives are perpendicular. The knife blades are preferably right-triangular in elevation and may be made from glass or other suitable material or have diamond cutting surfaces. For best results, the cutting apex of the knife triangle is inclined slightly toward the specimen 7.

FIGS. 6-10 show the improved guide plate 28 of this invention which is slidably attached to vertical frame 5 by any conventional means. Guide plate 28 serves the same purpose in this invention as in United States Patent No. 2,948,190. The purpose of this plate is described in detail in Patent No. 2,948,190. Essentially, the plate 28 changes the contour of aperture 29 in frame 6 through which specimen advancing bar 3 passes. Bar 3 follows the outline of aperture 29 and consequently the cyclical route of travel of bar 3 is changed depending upon whether plate 28 is in the full-out, intermediate, or fullin position. Detents in plate 28 are spaced so that when plate 28 is full-out bar 3 passes downward in line with knife blade 23. When plate 28 is in the intermediate position, bar 3 passes downward in line with knife 24, and when plate 28 is full-in, bar 3 bypasses both knife blades. The contour of plate 28 and the means of attachment to frame 5 is as described in Patent No. 2,948,190, except that in this invention plate 28 has an intermediate enlargement 31 in slot 32 in addition to enlargement 33.

In operation, knife 24 is adjusted so as to be directly in line with the downward stroke of bar 3 when plate 28 is in the intermediate position and knife 23 is adjusted so as to be directly in line with downward stroke of bar 3 when plate 28 is in the full-out position. By moving plate 28 alternately from the intermediate to the full-out position at each successive adavnce of the specimen, the specimen is caused to be pressed first against blade 24 and then against blade 23, and so on. The movement of plate 28 can be controlled either manually or automatically. The method of advancing the specimen in fixed increments is the same as in the microtome shown in Blums patents. Each pair of specimen sections cut from blades 23 and 24 are placed side by side for viewing in an electron or conventional microscope. Because the sections have been taken along perpendicular planes, the section structure under study will be shown in depth as well as cross section and consequently a more accurate reconstruction of the cells or organelles is possible.

The independent lateral and longitudinal adjustment means of this invention ar enecessary to allow proper positioning of the two knives before and during the cutting operation. The lateral movement permits use of that portion of the cutting surface which will produce the best sections. The longitudinal together with the lateral control provides for proper knife alignment with respect to the specimen.

It is to be understood that this invention is not limited to the taking of biological specimen sections. It is likewise to be understood that the configuration of knife blades need not be limited to the embodiment shown. They could, for example, be placed one above the other or in any other configurations in which their cutting surfaces are perpendicular to one another.

I claim:

1. In a microtome having specimen cutting means and means for advancing the specimen toward the cutting means in fixed increments, and wherein said specimen is movable in a plurality of directions relative to said cutting means, an improvement in the cutting means comprising a knife-holding stage having two knives, the cutting surfaces of which are in different planes, whereby as said specimen is passed over each knife cutting surface, specimen sections are obtained through different planes of the specimen.

2. The improvement in cutting means described in claim 1, wherein the two knife cutting surfaces are substantially perpendicular and wherein the sections obtained by passing the specimen over each knife cutting surface are taken from substantially perpendicular planes of the specimen.

3. In a microtome having specimen cutting means and means for advancing the specimen toward the cutting means in fixed increments, and wherein said specimen is movable in a plurality of directions relative to said cutting means, an improvement in the cutting means comprising a knife-holding stage having two knives, each knife having mounting means independently movable laterally and longitudinally relative to the stage.

4. The improvement in cutting means described in claim 3 wherein each knife mounting means has course and fine adjustment means for independently moving the mount laterally and longitudinally relative to the stage.

5. The improvement in cutting means described in claim 3 wherein the cutting surfaces of the two knives are substantially perpendicular, and wherein the knife blades are releasably mounted at an angle of approximately 45 degrees with respect to the axis of lateral knife movement.

6. In a microtome having specimen cutting means including two cutting surfaces and means for advancing the specimen toward the cutting means in fixed increments including a specimen holder, and wherein said specimen is movable in a plurality of directions relative to said cutting means, a guide means for cyclically passing the specimen against one cutting surface during one portion of the cycle, bypassing the cutting surfaces during the remaining portion of the cycle, and passing the specimen against the other cutting surface at the beginning of the next cycle. Y

7. The means for cyclically passing the specimen against the cutting surfaces as described in claim 6, wherein said guide means comprises a movable guide plate which presses against the specimen holder to constrict or expand the contour of the cyclical movement of the specimen, said plate having three detents, one causing the specimen to bypass the cutting surface, one causing the specimen to be passed against one cutting surface, and the third causing the specimen to be passed against the other cutting surface.

References Cited by the Examiner UNITED STATES PATENTS WILLIAM S. LAWSON, Primary Examiner. 

1. IN A MICROTOME HAVING SPECIMEN CUTTING MEANS AND MEANS FOR ADVANCING THE SPECIMEN TOWARD THE CUTTING MEANS IN FIXED INCREMENTS, AND WHEREIN SAID SPECIMEN IS MOVABLE IN A PLURALITY OF DIRECTIONS RELATIVE TO SAID CUTTING MEANS, AN IMPROVEMENT IN THE CUTTING MEANS COMPRISING A KNIFE-HOLDING STAGE HAVING TWO KNIVES, THE CUTTING SURFACES OF WHICH ARE IN DIFFERENT PLANES, WHEREBY AS SAID SPECIMEN IS PASSED OVER EACH KNIFE CUTTING SURFACE, SPECIMEN SECTIONS ARE OBTAINED THROUGH DIFFERENT PLANES OF THE SPECIMEN. 